EXHIBIT 15

July 28, 2004

USG Corporation
125 South Franklin Street
Chicago, Illinois 60606

We have made a review, in accordance with standards of the Public Company
Accounting Oversight Board (United States), of the unaudited interim financial
information of USG Corporation and subsidiaries for the three month and six
month periods ended June 30, 2004 and 2003, as indicated in our report dated
July 28, 2004; because we did not perform an audit, we expressed no opinion on
that information.

We are aware that our report referred to above, which is included in your
Quarterly Report on Form 10-Q for the quarter ended June 30, 2004, is
incorporated by reference in Registration Statement Nos. 33-40136, 33-64217, and
33-60563 (as amended) on Form S-3, Registration Statement Nos. 33-22581 (as
amended), 33-22930, 33-36303, 33-52715, 33-63554, and 33-65383 on Form S-8, and
Registration Statement Nos. 33-52573 on Form S-1.

We also are aware that the aforementioned report, pursuant to Rule 436(c) under
the Securities Act of 1933, is not considered a part of the Registration
Statements prepared or certified by an accountant or a report prepared or
certified by an accountant within the meaning of Sections 7 and 11 of that Act.

/s/ DELOITTE & TOUCHE LLP

DELOITTE & TOUCHE LLP

Chicago, Illinois